RF Antenna distribution- Headend equilazation
OK, guys, where is the best place to do headend equalization?
Attic - near antenna
Before distribution AMP
The system will have a Mast mounted amp fed from an attic injector.
Because signal strengths are all over the place, I was thinking about doing headend equlization over about 8 bands of UHF and 2 of VHF.
Most stations are UHF, but 2 are VHF stations. Rotor will have power and signal via a dedicated RG-6 feed. The Antenna has a single downlead. Antenna will be this one: **broken link removed**
I forget the model of the AMP. I think it's the AP-8700 with specs of: The Winegard AP-8700's specs are as follows: • Gain: VHF 17dB / UHF 19 dB • Noise: VHF 2.8 dB / UHF 2.8 dB
To do the equalization, I will have to separate the UHF/VHF and recombine after the equalization. Those would result in a 0.5 db loss when separating and a 0.5 db loss when combining again.
I would have the opportunity to attenuate the UHF or VHF separately in case of overloads.
There would be about 50' of RG-6 before it hits the headend distribution. Currently there are three 4-way taps for the distribution.
I do now have the means of measuring the signal strengths and the tap losses. Currently there is also a tilt compensator at the input of the distribution amp.
So, where is the best place to level the RF?
Attic? The temperatures would be a bit high, but it looks like the right place to put it.
Basement? Just before distribution?
I think the best spot will be the attic.
Predicted values of Noise Margin, are:
The present setup, which is a real zoo, I cannot receive 12 or 17 at all an who knows why. Also not sure what single edge and double edge refraction means in terms of reception. It could mean that double edge is more weather sensitive?
If anybody can answer what effect tilt has on UHF/VHF signal reception, I'd be grateful.
There will be antenna sensitivities and coax vs frequency attenuations as well, so higher frequencies will get attenuated more in distribution.
I'm aware it, an entire non-linear mess and am prepared that there will be lots of engineering to distribute this right. I may have to change some taps as well once I figure out what I have and what I need.
NM: This is the predicted Noise Margin (NM) of each channel "in the air" at your location, specified in dB. You must add/subtract any gains/losses you get from your antenna, building penetration, amps, cables, splitters, and other factors present in your situation. Hypothetically speaking, you need to end up with an NM value above 0 in order to pick up a station.
OK, guys, where is the best place to do headend equalization?
Attic - near antenna
Before distribution AMP
The system will have a Mast mounted amp fed from an attic injector.
Because signal strengths are all over the place, I was thinking about doing headend equlization over about 8 bands of UHF and 2 of VHF.
Most stations are UHF, but 2 are VHF stations. Rotor will have power and signal via a dedicated RG-6 feed. The Antenna has a single downlead. Antenna will be this one: **broken link removed**
I forget the model of the AMP. I think it's the AP-8700 with specs of: The Winegard AP-8700's specs are as follows: • Gain: VHF 17dB / UHF 19 dB • Noise: VHF 2.8 dB / UHF 2.8 dB
To do the equalization, I will have to separate the UHF/VHF and recombine after the equalization. Those would result in a 0.5 db loss when separating and a 0.5 db loss when combining again.
I would have the opportunity to attenuate the UHF or VHF separately in case of overloads.
There would be about 50' of RG-6 before it hits the headend distribution. Currently there are three 4-way taps for the distribution.
I do now have the means of measuring the signal strengths and the tap losses. Currently there is also a tilt compensator at the input of the distribution amp.
So, where is the best place to level the RF?
Attic? The temperatures would be a bit high, but it looks like the right place to put it.
Basement? Just before distribution?
I think the best spot will be the attic.
Predicted values of Noise Margin, are:
Real Channel # | NM(db) | Path |
---|---|---|
6 | 37.4 | 2edge |
34 | 33.2 | 2edge |
26 | 32.9 | 2edge |
17 | 31.6 | 2edge |
12 | 28.4 | 2edge |
32 | 62.7 | 1edge |
35 | 64.1 | 2edge |
29 | 65.1 | 1edge |
25 | 66.1 | 2edge |
31 | 26.4 | 2edge |
44 | 26 | 1edge |
27 | 23.6 | 2edge |
The present setup, which is a real zoo, I cannot receive 12 or 17 at all an who knows why. Also not sure what single edge and double edge refraction means in terms of reception. It could mean that double edge is more weather sensitive?
If anybody can answer what effect tilt has on UHF/VHF signal reception, I'd be grateful.
There will be antenna sensitivities and coax vs frequency attenuations as well, so higher frequencies will get attenuated more in distribution.
I'm aware it, an entire non-linear mess and am prepared that there will be lots of engineering to distribute this right. I may have to change some taps as well once I figure out what I have and what I need.
NM: This is the predicted Noise Margin (NM) of each channel "in the air" at your location, specified in dB. You must add/subtract any gains/losses you get from your antenna, building penetration, amps, cables, splitters, and other factors present in your situation. Hypothetically speaking, you need to end up with an NM value above 0 in order to pick up a station.
Last edited: